Ya know, I have looked into the pro's & con's reported on here about Baro's & after reading this one I've got to question the dependability, & reliability of pursuing this topic anymore for my particular stove set up??????????????? I know I damn sure don't want to install an Erector Set style gizmo on the old HITZER:( BUT, if it works, it's good:)

the lower MPD keeps heat in the stove, the upper MPD brings the draft down to where the Baro. can work as intended to prevent over draft during higher winds but not produce a constant draw of room air out the chimney 24/7.

last night i had 6-9 mph winds and could not induce the stove to go positive with both MPD's closed while the Baro. and intake where held wide open. the mano. reading was -.005.

rberq wrote:I did. Fire was really blazing up with new coal and lots of air. I closed the MPD and got lots of smelly smoke in the room, complaints from the wife department, 10 on the CO detector. Lesson learned.

It seems to me, that you should have closed, of cut down, the "under fire draft", while leaving the MPD slightly cracked. ??

Big fire, MPD suddenly closed, where's the smoke to go except out through leaky stovepipe joints or the air inlets?I don't think it was burning paint, because the stove had not yet heated up a lot, just had lots of fresh coal and lots of gas flaming up.Dallas is right, I could have slowed the fire by closing off the intake air, but I didn't want to slow the fire, I wanted HEAT. Or I could have just waited 15 minutes until the fire calmed down, THEN I could have closed the MPD without a problem.Could have done most anything except what I did do.

Big fire, MPD suddenly closed, where's the smoke to go except out through leaky stovepipe joints or the air inlets?

Are you sure that you have the correct size MPD? If you are using 6" pipe, there should be a "6 inch" embossed on the MPD. A 6" MPD, in a 6" pipe, is pretty loose (1/4" gap all the way around the perimeter, as well as multiple holes in the plate).

My stove burns fine with the MPD closed, regardless of the under fire draft .. wide open or closed.

Dallas, I've heard people mention SOLID ones on here--never saw such a critter myself, nor could I imagine anyone buying one--BUT--who knows anymore--might be one of those BETTER IDEA silly concepts. I also can keep mine closed all the time with no negative happenings--I'm thinkin more chimney draw then MPD????????????????????? AGAIN, who knows:(

click on link above, it's the owners manual for a Harman Mark I or Mark III coal stove. When you click on it, wait until the PDF file opens, then scroll down to page 7, section 3.1

here's what it says:UNDER NO CIRCUMSTANCES SHOULD A MANUAL FLUE DAMPER BE INSTALLED IN THE SMOKE PIPE BETWEEN THE STOVE AND THE CHIMNEY.

then read the bottom of page 6, here's what it says:

MANUAL DAMPERS OR “HEAT SAVERS” MUSTNEVER BE INSTALLED IN THE FLUE PIPE. IMPROPEROPERATION COULD RESULT IN DEATH.

that's the final say in stove pipe dampers of any kind, including baro dampers, on any antique or modern stove, using a recirculating type exhaust design, to extract more heat from the stove. Stoves of this type are already internally baffled and dampened. Putting another damper in the stove pipe on such stoves, risks death from CO backing up into the room and home.

having said that, relying on a damper as such, to get "efficiency" from a stove made in the 1920's, is risking your life and your family's life. We've learned a little since then. These recirculating exhaust stoves should not have a damper in the stovepipe.

Only use a stovepipe damper on a wood stove, or very cautiously on a coal stove, providing the coal stove is not internally baffled already. There are differences between manual damper design for coal and wood stoves. A coal stove damper has holes drilled in the middle and will still pass 20% of total volume when fully closed. A wood stove damper will have no holes in the middle.

Ask yourself why those holes are in the middle of the damper, for the coal stove. Because the CO gases from coal, are deadly.

That's playing with fire, literally. I sleep very well knowing there's no manual damper on the flue pipe of my Harman I. Flue pipe damper SPRINGS do wear out from heat, and then the damper becomes loose and doesn't hold it's adjustment. This $6 hardware store mechanism can kill you, if it blocks the stove pipe on a coal stove, that's internally baffled. Never install a solid damper on a coal stove. The risk is not not worth any amount of efficiency or money you may save.

These tall free standing "oak" style vintage stoves of the recirculating design, fall into this category. Proceed with caution.

Last edited by coalcracker on Sat Dec 07, 2013 2:01 pm, edited 1 time in total.

I'm HOPING that anyone burning a coal devise of any type understands the risks & has CO detectors. Be it MPD, Baro, furnace, boiler, hand fired or whatever--my MPD serves me well & safely with my stove. I'm not a big Baro fan, but I'm not going to conclude they are more DEADLY then anything else because I find an article that supports my personal beliefs.